I have a very good friend who is CP and her husband is also CP. He (not she) has had MANY bouts with taking too many meds, Dr shopping, and Lord knows what else. He was very badly injured (actually crushed between two cars) and also has horriffic migraines and chronic extreme sinus infections.
He has been hospitalized multiple times for overdoing the meds and has had some serious conditions develop from them....but....he is is very serious pain as well. It sounds a lot like your husband in that he is surely in pain (11 back surgeries is pain forever, I'm afraid). I don't know the answer, but I do know that she found his "drug of choice" which was not one of the "biggies", but was zanaflex and took care of the problem by making his meds up every day and including 1 zanaflex and three vitamin pills exactly the same size. Now he doesn't even realize he was abusing and he doesn't know that his meds are different. He just honestly believed if one helps, four are better. Of course this made him a danger to himself and others. I don't recommend messing with someone else's meds ever, but my friend made that decision and it has worked better than any other thing they have ever tried (about 22 years). The serious meds (Oxy, Opana, Kadien, Suboxone, Methodone) never were a problem for him....it was the Zanaflex that gave him the uncontrollable behavior.....also Ambien did the same for him (but he was hateful and sometimes a little dangerous witht the Ambien). She freaked when I started using it, but I have no problem. It was just his body didn't respond like the "normal" person.
I mention the medication names because each med works so differently with each person. I do not mean to imply that any med is bad or good...but that some work for one person and can cause awful reactions in another.
If your husband had a single "drug of choice" that was the link, perhaps there could be something done about that one. Otherwise, NarcAnon, AlAnon, and programs like that might be helpful to understanding your role in the addiction process.
You sound as if you are doing all you can and I applaud you for that. Please know, however, that you did not cause this problem, you cannot cure this problem and you are not responsible for this person's actions.
I wish you all the best!
Failed fusion L5-S1, Pituatary damage, HGH Def, Fibro, Bladder surgery failure, Nissen Failure, GERD, OCPD, GAD, MDD, CTS (Bilateral Surgery completed), CFS, TMJ, Migraines, Vit D, A, Magnesium deficiency, Pre-glaucomic (sp?), HBP, Idiopatic Reactive Hypoglycemia, Edema, too many Drug/Food allergies, sensitivites, and current meds to list.